Study on the Strip Warpage Issues Encountered in the Flip-Chip Process

This study successfully established a strip warpage simulation model of the flip-chip process and investigated the effects of structural design and process (molding, post-mold curing, pretreatment, and ball mounting) on strip warpage. The errors between simulated and experimental values were found to be less than 8%. Taguchi analysis was employed to identify the key factors affecting strip warpage, which were discovered to be die thickness and substrate thickness, followed by mold compound thickness and molding temperature. Although a greater die thickness and mold compound thickness reduce the strip warpage, they also substantially increase the overall strip thickness. To overcome this problem, design criteria are proposed, with the neutral axis of the strip structure located on the bump. The results obtained using the criteria revealed that the strip warpage and overall strip thickness are effectively reduced. In summary, the proposed model can be used to evaluate the effect of structural design and process parameters on strip warpage and can provide strip design guidelines for reducing the amount of strip warpage and meeting the requirements for light, thin, and short chips on the production line. In addition, the proposed guidelines can accelerate the product development cycle and improve product quality with reduced development costs.

Modeling of Leadframe Strip Warpage after Die Attach Cure Process

In the leadframe package assembly process, silicon die is attached to the leadframe using a die attach adhesive material and the bonded strip is then cured. However, excessive strip warpage after the die attach cure process is a challenging problem that also affects the succeeding assembly processes. In this study, strip warpage modeling was done using a finite element analysis (FEA) technique to understand the warpage mechanism after die attach cure and find options to reduce strip warpage. The effect of changing the leadframe thickness, die thickness, and the leadframe design in terms of the number of strip panels or changing the connecting bar was analyzed. Modeling demonstrated that lead frame contracts faster than the silicon die resulting in the “frowning” warpage that agrees with the actual observation. It was also shown that increasing the die thickness by 25% results in 27% warpage reduction. Results also showed that increasing the number of panels or maps in a strip could significantly reduce the strip warpage. Improving the panel-to-panel isolation using stress relief cuts is also another option to reduce warpage after die attach cure.

Study of tube billet reduction to obtain constant wall thickness

Analysis of material thickening process during reduction operation is presented. In order to obtain constant thickness after reduction by conical die thickness distribution of the workpiece is proposed. Workpiece with required thickness distribution is manufactured by thinning drawing. Experimental verification of proposed thickness distribution in order to obtain constant thickness after reduction operation is carried out.

157 The effect of different inclusion levels of corn starch and fine ground corn with different conditioning temperatures or die thickness on pellet quality

The objective of this experiment was to determine the effect of different inclusion levels of corn starch and fine ground corn with different conditioning temperature or die thickness on pellet quality. Experiment 1, treatments were arranged in 3×2 factorial design of corn starch inclusion level (0, 5 and 10%) and die thickness (4mm×13mm and 4mm×22 mm). Experiment 2, treatments were arranged in 3×2 factorial design of fine ground corn inclusion level (0, 10 and 20) and conditioning temperature (80 and 85°C) with treatments pelleted using a 4mm×22mm die (5.6 L:D). In both experiments, treatments were pelleted using a model CL-5 CPM pellet mill (Crawfordsville, IN). The result of experiment 1 demonstrated that there was no interaction between corn starch inclusion level and die thickness on modified pellet durability index (PDI), (P=0.636). Increasing die thickness from 12.7 to 22.2 mm increased PDI from 43 to 70% (P< 0.001). There was a linear decrease (P< 0.001) in PDI as the corn starch inclusion level increased from 0 to 10% (64, 60, and 46%, respectively). The result of experiment 2 demonstrated that there was no interaction between fine ground corn inclusion level and conditioning temperature on PDI (P=0.541). The fine ground corn inclusion level did not impact PDI (P=0.298). Increasing conditioning temperature from 80 to 85°C increased PDI (P< 0.001) from 76 to 85%, respectively (P< 0.001). Based on the results, the use of pure corn starch was not an effective binding agent in the feed when the diet contains at least 60% ground corn. The ratio of small corn particles to large corn particles in the diet did not impact pellet quality when the diets were conditioned above 80°C for 35 sec and then pelleted with a 5.6 L:D die. Increasing die thickness and conditioning temperature improved pellet quality.

50 Pelleting and Starch Characteristics of Diets Containing Enogen® Feed Corn

This experiment determined the effects of die thickness and conditioning temperature on pelleting and starch characteristics in diets containing conventional or Enogen® feed corn (Syngenta Seeds, LLC). Treatments were arranged as a 2 × 2 × 3 factorial of corn type (conventional [CON] and Enogen® feed corn [EFC]), die thickness (5.6 and 8.0 length:diameter [L:D]), and conditioning temperature (74, 79, and 85°C). Diets were steam conditioned and pelleted (CPM Model 1012-2) with a 4 × 22.2 mm or 4 × 31.8 mm pellet die. Conditioner retention time was set at 30 s and production rate was set at 15 kg/min. All treatments were replicated on 3 separate days. Data were analyzed using the GLIMMIX procedure in SAS (v. 9.4, SAS Institute Inc., Cary, NC). Increasing die L:D improved PDI (P=0.01) and increased (P=0.02) energy consumption. Increasing conditioning temperature from 74 to 85°C increased (linear, P< 0.03) PDI (84.2, 84.9, and 88.2%, respectively) and tended to decrease energy consumption (quadratic, P=0.07). There was a corn × conditioning temperature interaction (P=0.01) for gelatinized starch in conditioned mash. Enogen® feed corn diets steam conditioned at 85°C had the greatest quantity of gelatinized starch. Cooked starch of conditioned mash was greater (P< 0.01) for EFC diets compared to CON diets and increased (linear, P< 0.01) with increasing conditioning temperature. Starch gelatinization was greater (P< 0.01) in pelleted EFC diets (13.4%) compared to CON diets (11.7%) and was increased (linear, P=0.05) by increasing conditioning temperature from 74 to 85°C (12.0, 12.1, and 13.4%, respectively). Pelleted diets containing EFC had increased (P< 0.01) cooked starch compared to CON diets. In conclusion, increasing die L:D and increasing conditioning temperature improved PDI. Starch gelatinization was increased when diets were pelleted at the highest conditioning temperature of 85°C, and EFC diets resulted in greater gelatinized starch.

PSVIII-6 Effect of Pellet Die Thickness and Conditioning Temperature During the Pelleting Process on Phytase Stability

This experiment evaluated the effects of pellet die thickness and conditioning temperature on microbial phytase stability. Treatments were arranged as a 2 × 3 factorial of die thickness (5.6 and 8.0 length:diameter [L:D]) and conditioning temperature (74, 79, and 85°C). Phytase was added to a corn-soybean meal-based diet. The diet was steam conditioned (245 × 1397 mm Wenger twin staff pre-conditioner, Model 150) and pelleted (CPM Model 1012-2) with a 4 × 22.2 mm (5.6 L:D) or 4 × 31.8 mm (8.0 L:D) pellet die. Conditioner retention time was set at 30 s and production rate was set at 15 kg/min. All treatments were replicated over 3 days. Conditioned mash and pellet samples were collected and immediately placed in an experimental counter-flow cooler for 15 min. Samples were analyzed for phytase activity and pellet durability index (PDI). Conditioning temperature, hot pellet temperature (HPT), and production rate were recorded throughout each processing run. Data were analyzed using PROC GLIMMIX in SAS (v. 9.4), with pelleting run as the experimental unit and day as the blocking factor. There was no evidence (P >0.14) for any die thickness × conditioning temperature interactions. Pelleting with the 8.0 L:D die increased (P < 0.01) HPT (83.2 and 84.2°C) and PDI (81.9 and 89.7%). Increasing conditioning temperature from 74 to 85°C increased (linear, P< 0.03) HPT (80.1, 83.6, and 87.5°C , respectively) and PDI (84.3, 84.9, and 88.2%, respectively) and decreased (linear, P< 0.01) phytase stability from 97.1 to 35.8% in conditioned mash and from 60.8 to 25.9% in cooled pellets. There was no difference (P >0.72) in stability due to die thickness. Results of this experiment demonstrated phytase stability decreased linearly as temperature rose above 74°C. Although the thicker pellet die increased HPT and PDI, the rise in HPT was not great enough to reduce phytase stability.

Pelleting and starch characteristics of diets containing different corn varieties

This experiment determined the effects of die thickness and conditioning temperature on pelleting and starch characteristics in diets containing conventional or Enogen Feed corn (Syngenta Seeds, LLC). Treatments were arranged as a 2 × 2 × 3 factorial of corn type [conventional (CON) and Enogen Feed corn [EFC]), die thickness [5.6 and 8 length:diameter (L:D)], and conditioning temperature (74, 79, and 85 °C). Diets were steam conditioned (Wenger twin staff preconditioner, Model 150) and pelleted (CPM, Model 1012-2) with a 4- × 22.2-mm (L:D 5.6) or 4- × 31.8-mm (L:D 8) pellet die. Conditioner retention time was set at 30 s and production rate was set at 15 kg/min. All treatments were represented within three replicate days. Pellets were composited and analyzed for gelatinized starch and pellet durability index (PDI). Conditioning temperature, hot pellet temperature, production rate, and pellet mill energy consumption were recorded throughout each processing run. Data were analyzed using the GLIMMIX procedure in SAS (v. 9.4, SAS Institute Inc., Cary, NC) with pelleting run as the experimental unit and day as the blocking factor. Pelleting with a larger die L:D improved PDI (P = 0.01) and increased (P = 0.02) pellet mill energy consumption. Increasing conditioning temperature from 74 to 85 °C increased (linear, P < 0.03) PDI and tended to decrease energy consumption (quadratic, P = 0.07). There was a corn × conditioning temperature interaction (P = 0.01) for gelatinized starch in conditioned mash. Enogen Feed corn diets steam conditioned at 85 °C had the greatest quantity of gelatinized starch. Cooked starch in conditioned mash and pellets was greater (P < 0.01) for EFC diets compared to CON diets and increased (linear, P < 0.01) with increasing conditioning temperature in conditioned mash. Similarly, starch gelatinization was greater (P < 0.01) in pelleted EFC diets compared to CON diets and was increased (linear, P = 0.05) by increasing conditioning temperature from 74 to 85 °C. In conclusion, increasing die L:D and increasing conditioning temperature improved PDI. Starch gelatinization was increased when diets were pelleted at the highest conditioning temperature of 85 °C, and EFC diets resulted in greater starch gelatinization than conventional corn.

Optimization of multiple performance responses of a fish feed pelletizer machine

This study details the assembling of a prefabricated fish feed pelletizing machine and optimization of some operational parameters such as die thickness, number of die holes, shaft speed and feed rate to produce high-grade fish pellets. The Taguchi methodology and Grey relational analysis (GRA) have been utilized to evaluate the multi-objective functions of interest such as pelletizing efficiency, throughput, energy requirements and pellets bulk density (g/cm3). The pelletizer machine performance evaluation test was carried at 3 levels of die thickness (8, 6 and 12 mm), number of die holes (30, 25, and 35), and feed rates (145, 130 and 160 g/h). The test for the performance indicators was conducted using L9 orthogonal array experimental design. The test data were analyzed using the Taguchi scheme employing the signal-to-noise ratio response with effects deduced. The GRA was utilized to assess multiple responses by fusing the Taguchi technique with the GRA. Thus the multi-objective optimization was transformed to a single equivalent objective function. The results of Taguchi optimization revealed that die thickness was the most influential parameter for the various control factors. In addition, optimum parameter combination was obtainable at medium die thickness (8mm), medium number of die holes (30), low shaft speed (200rpm) and medium feed rate of 145g/h. Analysis of variance for grey relational grade (GRG) reveals that die thickness and feed rate are the dominant parameters. The confirmation test performed shows that the GRG is enhanced by 2.19%.